This invention relates to a tap wrench and in particular to a compact, simple hand-operated tap wrench including a reversible ratchet mechanism.
Ratchet wrenches are well known for a variety of purposes. It has long been recognized as desirable to have a ratchet wrench which is compact and therefore easy to transport and capable of being used in restricted quarters where attachment and movement of the wrench may be quite limited. In such quarters, it may also be desirable to change the direction of ratcheting while the wrench is positioned in the work. At the same time, the wrench must be strong enough to withstand the rather substantial pressures which may be exerted on it. Presently known ratchet wrenches are not always totally adequate in these respects.
One type of ratchet wrench is used for hand-tapping of female threads on the inner surfaces of holes in stock material. In part, these hand taps have the same requirements as other ratchet wrenches. In addition, they must be designed to provide accurate alignment of the wrench and reduce cocking of the tap with respect to the hole. The amount of torque which the user can apply should also be limited when small taps are used and greater when large taps are used. The range of tap sizes which can be accommodated should also be as large as possible. Presently, several different wrenches are required to handle the full range of common taps, from 10/32 (about 0.1875" in diameter) to 5/8 (about 0.625" in diameter). The shank diameter of each tap may vary from manufacturer to manufacturer, and from size to size of the tap. It would be highly desirable to have a universal tap wrench which could be used with taps of a wide range of sizes.